No, I think it could be... say there's a large something, but they've got their assignments from different (maybe competing) sources, so they decide to... I dunno, team up? And worry about who gets to keep the creature's head later?
(Maybe even one each, if it has multiple heads or there turns out to be multiple creatures?)
Maybe they started off at odds with each other, but then each tried to go for the monster and ended up retreating to save their lives? Maybe the second team retreats and gets chased by something other than their target, and manages to stumble onto the first team's camp - who then help slay the monster, and that's when they decide to team up?
Alternatively, what if they've both been hired for the same target because the employer wants a larger team to go after it, so he introduces them to each other and at first they're at odds with each other but after being out in the field and facing down monsters whilst tracking down their target, they learn to get along grudgingly?
Like, they start out with both teams basically refusing to listen to or interact with the other, then someone has a good idea or takes control of instructions in a fight (maybe they lost badly, and that's what triggers the truce?) and the team leaders start bickering over instructions but manage to work together somehow, and maybe my Melline begins trying to talk to your Greythorn sisters because Merpsichore isn't exactly conversational? IDK lol